Reply to tractor S4MK2 & traktor DJ lacking low end?

i recently changed over form the audio 8 and my laptop (using the x1) to the S4MK2 & traktor DJ- and the low end seems to be lacking seriously.. is this an app thing with the iPad or the S4's sound card? to be fair.. haven't tried the S4 with my laptop yet.. and using 1/4 ins with a coupler for my mackies into S4. Any direction would be helpful.

Thanks!